speculativeevolutionfandomcom-20200216-history
Spec: Mosasauria
Rivaling the dinosaurs as the most famous prehistoric animals are the great marine reptiles that mastered the Mesozoic oceans. On Home-Earth, the sea turtles are a sole reminder of a lost age when sauropsids ruled the waves. Beneath the waters of Spec however, the turtles are joined by another, far less benign lineage from the Cretaceous, the fearsome mosasaurs. Mosasaurs are aquatic anguimorph lizards related to monitors and snakes, falling phyletically somewhere in between them. They are found throughout the warmer waters of the world, ranging in size from 2 to over 20 metres in length. Their bodies have become superbly adapted to aquatic life, with all four limbs having evolved into hydrodynamic paddles that are lengthened by an increased number of phalanges. All species are ovoviviparous, giving birth to live young and need never come ashore. Both the skull and lower jaw have special hinges that create a massive bite combined with a surprising degree of fine manipulation - a mosasaur can break open an ammonite shell and gobble down the contents without shattering it. The variety of dentition displayed by modern mosasaurs far outdoes any other lizard group, ranging from densely packed needles to sparse crushing pegs. Most mosasaurs have good eyesight and hearing but, in extant forms at least, the strongest sense appears to be chemoreception. All mosasaurs possess a well developed set of Jacobson's organs that allows them to "smell" the water by passing it over the roof of the mouth. Although their underwater sense of smell has yet to be scientifically quantified, it appears to rival that of sharks in that dumping chum on the surface of the Spec sea will attract every lizardwhale for miles around. =MOSASAUR HISTORY= Mosasaurs evolved from smaller lizards called aigialosaurs that took the water during the mid-Cretaceous. Rapidly increasing in size and diversity, the early mosasaurs soon became top marine predators and spread across the globe. This first generation were sinuous creatures with short paddles and a long, flattened tail that swam with an undulating motion much like a crocodile or snake. Not designed for prolonged chases, they probably ambushed prey with sudden bursts of speed. Monsters like Hainiosaurus and Tylosaurus terrorized the Maastrichtian seas from the Netherlands to New Zealand but, despite all their evolutionary vigor, were obliterated by the KT catastrophe of Home Earth. Perhaps this was in part for being largely restricted to the continental shelves and inland seas whose ecosystems were hit particularly hard. In the early Cenozoic of Spec, mosasaurs continued to flourish and diversify while many other aquatic reptiles, like elasmosaurs and polycotylids, went into decline. 20 metre long tylosaurines cruised the Eocene seas from the shores of the Tethys to the warm Antarctic coast. But these relics of the Cretaceous were condemned by the climatic chaos that struck the Late Eocene world. Just as the serpentine archaeocete whales of our timeline perished at this time, so too did their reptilian counterparts on Spec. However the Late Eocene proved to be a new beginning for the clade, for other mosasaurs had branched into different habitats and body-forms that made them better able to endure those troubled times. Some took the elongated body-form of their ancestors to the next level, becoming serpentine masters of murky, weed-choked rivers. Another group took to the open ocean, turning their bodies into piscine torpedoes that could outswim their fastest prey. Today, a dazzling array of mosasaurs can be found from the equator to the warm-temperate waters across the globe. While barred from the polar regions owing to their cold-blooded metabolisms, the size and variety of Spec's modern Mosasauria puts their Cretaceous ancestors to shame. They can be divided into two broad groupings - River mosasaurs – elongated, serpentine creatures with needle-like teeth that dwell in the tropical fresh and brackish waters of the Old World. Saurocetaceans - a highly successful radiation of fish-shaped predators that rule the open seas. ,=Anguillacertidae =Mosasauria=| | ,=Archaeosaurocetacidae `=| `=Saurocetacea Brian Choo Category:Spec Dinosauria Category:Animals Category:Reptiles Category:Squamates Category:Aquatic Creatures Category:Alternative timelines Category:Alternative evolution Category:Asia Category:Antarctica Category:Arctic Category:Pacific Ocean Category:Atlantic Ocean Category:Indian Ocean Category:Europe Category:Africa Category:Craniates Category:Amniotes Category:Sauropsids Category:Carnivores